Example embodiments relate to endoscopic systems. Endoscopic system includes main body and control section. Control section includes extendible section that extends and contracts to change length between extendible section ends. Control section includes first expandable member. When first expandable member is in an expanded configuration, first expandable member includes proximal side wall and distal side wall. Distal side wall of first expandable member includes first protrusions. Control section includes second expandable member. When second expandable member is in an expanded configuration, second expandable member includes distal side wall and proximal side wall. Proximal side wall of second expandable member includes second protrusions. First and second protrusions configurable to cooperate to form a sieve portion between first and second expandable members. The sieve portion configured to reduce an occurrence of solids blocking pressure openings while allowing negative pressure to be applied to a body cavity wall through the pressure openings.
